Semiconductor production technology that achieves further miniaturization has been developed, and a line width of 20 nm or 10 nm has been used for a leading-edge process. The degree of difficulty in processing has increased along with an increase in the degree of miniaturization, and various techniques are currently under development using various approaches in terms of the materials, devices, and processing methods.
In view of the above situation, the applicant of the present application developed a plasma etching gas that includes a saturated fluorohydrocarbon represented by the formula (1): CxHyFz (wherein x is 3, 4, or 5, and y and z are independently a positive integer, provided that y>z) that can deal with a leading-edge dry etching process, and reported that a saturated fluorohydrocarbon having a small number of fluorine atoms exhibits a performance better than that of monofluoromethane that is used to etch a silicon nitride film (see Patent Literature 1).
For example, the following methods are known as a method for producing 2-fluorobutane (i.e., saturated fluorohydrocarbon represented by the formula (1)).
Patent Literature 2 discloses that 2-fluorobutane was obtained in a yield of 46% by bringing N,N-diethyl-3-oxomethyltrifluoropropylamine (fluorinating agent) into contact with 2-butanol.
Patent Literature 3 discloses that sec-butyl fluoride was produced by bringing sulfur hexafluoride into contact with a sec-butyllithium cyclohexane/hexane solution.
Patent Literature 4 discloses a method that brings 2-butanol into contact with a fluorine-containing ylide in the presence of 2-butene.
Patent Literature 5 discloses that 2-fluorobutane was obtained by hydrogenating 2-fluorobutadiene in the presence of a catalyst.
Non-Patent Literature 1 discloses a method that subjects an olefin compound to bromohydrination wherein methylenecyclobutane is reacted with aqueous N-bromosuccinimide in the absence of a solvent to obtain 1-(bromomethyl)cyclobutanol.
These pieces of literature disclose a method for producing 2-fluorobutane. However, these pieces of literature disclose only a little information about the purity of the resulting 2-fluorobutane as well as impurities, and do not disclose a method for efficiently purifying 2-fluorobutane.